Embryology of the GI tract Flashcards
What does the endoderm layer give rise to in the GU tract?
Epithelium of mucosa (epithelial lining)
Associated ducts and glands
What does the visceral mesoderm layer give rise to?
Lamina propria
Muscularis mucosa and Muscularis externa
CT of submucosa and External CT
What do the ventral mesenteries give rise to?
Lesser omentum
Falciform ligament
What do the dorsal mesenteries give rise to?
Dorsal mesogastrium
Dorsal mesoduodenum
Dorsal mesocolon
What does rotation of different parts of the gut bring about?
Brings the mesenteries into their final positions
Describe the development of the oesophagus? Week 4,5 and 8?
Week 4 - distinguishable
Week 5 - circular muscle develops
Week 8 - longitudinal muscle develops
How does the stomach develop?
The stomach develops as a dilatation in the foregut that rapidly enlarges asymmetrically, giving rise to the greater curvature of the stomach.
What does growth and rotation of the stomach creat?
Growth and rotation of stomach creates the lesser sac and causes the dorsal mesentery to bulge
Continued growth of the dorsal mesentery forms the greater omentum
How do the lesser omentum and the falciform ligament form?
Lesser omentum and falciform ligament form from the ventral mesentery
Describe how the duodenum is made?
The caudal portion of the foregut makes up the 1st and 2nd part of the duodenum
The cranial portion of the midgut forms the 3rd and 4th part of the duodenum
What happens to the duodenal loop as the stomach rotates?
the duodenal loop is directed to the right due to the rotation of the stomach
What does the liver bud grow into?
The mesoderm of the septum transversum
What does the endoderm form in relation to the liver and gall bladder?
Liver cells
Lining of the biliary tree
What does the ectoderm give rise to in the GI tract?
Lining of the closely related resp tract and some of the epithelial of the mouth and anus
What does the septum transversum give rise to in relation to the liver and gall bladder?
Hematopioetic cells
Kupffer cells
Connective tissue
What happens if the rotation of the pancreatic bud is incomplete?
If rotation of the pancreatic buds is incomplete, a ring of pancreatic tissue may surround the duodenum – called the annular pancreas.
What is the spleen derived from?
The mesoderm - NOT THE GUT TUBE
What is part of the midgut?
Second part of duodenum Jejunum Ileum Caecum and appendix Ascending colon Proximal 2/3 of transverse colon
Describe the re-entry of the midgut to the body cavity?
Occurs in week 10
Small intestine return first Caecum is last to reenter
What is a common congenital defect of the small intestine?
Merkel’s diverticulum - a small diverticulum in the intestine
